Electrical energy is widely employed during surgical procedures in which electrosurgical techniques are employed to provide localized high flux energy to tissue during open, laparoscopic, and arthroscopic applications to provide clinical benefits, such as hemostasis, relative to surgical approaches that use mechanical cutting such as scalpels. Electrosurgical techniques typically entail the use of a hand-held instrument, or pencil, that transfers alternating current electrical power operating at radio frequency (RF) to tissue at the surgical site. The time-varying RF electrical power yields a predetermined electrosurgical effect, such as tissue cutting or coagulation.
The process of applying RF electrical power causes high temperatures to occur in the tissue and on at least part of the surgical instrument. The result of these high temperatures is the formation of tissue fragments and other substances that often accumulate and form deposits on surgical instruments. These deposits are called eschar. Eschar frequently accumulates in such amounts that it interferes with surgical procedures.
In attempts to alleviate the formation of eschar or make instruments from which eschar may be more easily removed than from metal surfaces, instruments with surface coatings, such as coated blades, have been used or described. For example, such coatings are made from materials to which eschar accumulations stick less tightly than they stick to the metals from which electrosurgical instruments are made. The coatings are typically made from one or more polydiorganosiloxane or polytetrafluorethylene (PTFE) compounds. These compounds suffer from not having high temperature durability. Materials capable of withstanding high temperatures, such as ceramics, do not confer adequate non-stick properties when used as coatings. In this regard, the present inventors have recognized that the need exists for a high temperature coating that has non-stick properties.
Relatedly, the metal conductors in electrosurgical instruments that convey energy to tissue get hot during use. When contacting tissue the hot surfaces damage tissue. Therefore, protecting tissue in the use environment from the hot instrument surfaces can reduce tissue damage. Typical coatings cannot withstand the high temperatures in regions directly adjacent to where RF electrical power transfers to tissue. In this regard, the present inventors have also recognized that the need exists for a high temperature coating with insulating properties.
In general, the present inventors believe that the need exists for a coating that can protect component materials from the use environment and the use environment from components.